Alpheus is the chief river of Peleponnesus, rising in the southeast of Arcadia, and flowing past the famous Olympia westward into the Ionian Sea. In its passage through Arcadia, a country of cavernous limestone, it repeatedly disappears underground and rises again. With this fact was connected a remarkable myth. The river-god Alpheus was said to have become enamored of the nymph Arethusa while bathing in his stream. To escape him, she prayed to Artemis, who changed her into a fountain and opened up an underground passage for her to Ortygia, a small Sicilian island in the harbor of Syracuse. The river still pursued the nymph, passing from Greece to Sicily below the sea, without mingling his waters with it, and appearing in the spring that bubbles up by the shore, close by the fountain of Arethusa.